Graham Cluley reports on a multi-national, multi-agency takedown of the Simda botnet that is thought to have infected around 770,000 PCs around the world (www.grahamcluley.com; “A quick way to tell if your PC was infected by the Simda botnet”; April 14th).

Mr. Cluley’s article reports that Kaspersky has created an online test allowing individuals to see if their PC had been infected; the test checks the individual’s IP address against the database of infected IP addresses that the security experts had found. How did these PCs get infected? Mr. Cluley cites a Kaspersky blog that reports the Simda botnet initially got into the PCs through vulnerabilities that individuals hadn’t patched. It could also have been inserted via fraud malware that got installed.

Just another reminder, Mr. Cluley urges, that individuals need to update operating systems and third-party software (e.g., Flash, Adobe Reader) with the most current security fixes. He notes that doing so “…is an essential part of protecting your computer from attack and should be done alongside running up-to-date anti-virus software.”